H2020Индивидуална стипендия2015–2017

FLYghtCaRe · Ca2+ feedback control of TRP/TRPL channels in Drosophila photoreceptors

„Хоризонт 2020“ — Действия „Мария Склодовска-Кюри“

Период: 2015-11-01 → 2017-10-31
Финансиране от ЕС: 183 455 €
Участници: 1
Схема: MSCA-IF-EF-ST

Линиите свързват координатора с партньорите.

Накратко на български

Фоторецепторите на плодовата муха използват калциеви йони и специални канали, за да разпознават както единични фотони, така и силна дневна светлина. Разбирането на тези механизми помага да се разбере как окото регулира чувствителността си при различни нива на осветеност.

Този кратък обзор е генериран от изкуствен интелект

Кратко обяснение, генерирано от езиков модел по текста на CORDIS. Оригиналът е по-долу.

Резултати накратко

Ca2+ feedback control of TRP/TRPL channels in Drosophila photoreceptors

Vision begins in specialised cells (photoreceptors) where incident photons of light are converted into an electrical response (light-induced current) by a process known as phototransduction. Photoreceptors in both vertebrates and invertebrates must continuously adjust their sensitivity to cope with the huge changes in illumination over day and night. Invertebrate photoreceptors possess the most efficient light adapting mechanisms known. For example, photoreceptors in the fruitfly Drosophila can detect single photons, generating discrete amplified responses called ‘quantum bumps’, yet still respond reliably in full daylight. In contrast, quantum bumps in vertebrate photoreceptors (rods) are smaller and slower than in flies, whilst rods saturate already at medium light intensities. Calcium ions (Ca2+) are crucial for the fly’s impressive performance, leading to: (i) quantum bump amplification, (ii) fast responses, and (iii) gain control in light adaptation. Much of this is achieved by sequential positive and negative feedback of the light-induced currents mediated by Ca2+ entering the cell via ion channels known as TRP and TRPL. Both channels are negatively modulated by Ca2+, but positive feedback is specific to TRP.

Текст от CORDIS, на английски · Данни: CORDIS, © Европейски съюз

Цел на проекта

A major challenge for any visual system is the dramatic difference in ambient light between a starlit night and midday sun. In contrast to the ciliary rods of vertebrates, the rhabdomeric photoreceptors of the common fruitfly not only reliably detect single photons when dark-adapted (generating responses called ‘quantum bumps’), but continue responding in full daylight. At the core of this performance lie positive and negative feedback loops, many involving Ca2+ entry through the light activated transient receptor potential channels TRP and TRPL. Although Ca2+ modulates virtually every step of the phototransductive cascade, key targets are the channels themselves, leading to: (i) amplification by positive feedback during the rising phase of quantum bumps, (ii) gain reduction by negative feedback during quantum bump termination and during light adaptation. Our objectives are to combine single cell electrophysiology and optogenetics to explore Ca2+ signalling in fly photoreceptors, dissecting both its molecular interaction with TRP and TRPL channels and its dynamics within the cell. Our first aim will be to characterise the role of Calmodulin binding sites and other unknown regulatory sites on TRP and TRPL, in the feedback loops described above. Flies expressing mutated and chimeric TRP/TRPL channels will be used. Our second aim will be to obtain measurements of Ca2+ dynamics with subcellular spatial resolution under physiological illumination. Genetically encoded Ca2+ indicators will be targeted to specific cellular compartments and imaged in intact flies by exploiting the optics of the compound eye. Measurements will be made in fly mutants displaying defective light responses and retinal degeneration, leading to precise hypotheses on the mechanisms responsible for their phenotypes. This project will bring our understanding of rhabdomeric phototransduction to a new level of sophistication, while enriching my professional skills in a world-class laboratory.

Оригинален текст от CORDIS (на английски).

Участници

THE CHANCELLOR MASTERS AND SCHOLARS OF THE UNIVERSITY OF CAMBRIDGE · CAMBRIDGEКоординаторОбединеното кралство